Ultimate Energy Research Articles

Seismic performance of novel high-strength steel external assembled 3U energy dissipator

The development of easily implemented, cost-efficient, and replaceable energy dissipation devices is increasingly emphasized to improve bridge resilience. This study introduces a novel external assembled 3U energy dissipator (EA3UED) made of high-strength steel, designed to enhance the performance of precast segmental concrete bridge piers. The EA3UED, featuring three distinct U-shaped components to provide multi-directional resistance, was evaluated through comprehensive cyclic loading tests on five different specimens to assess their failure modes and practical feasibility. Finite element analysis conducted in Abaqus further assessed parameters such as ultimate bearing capacity, energy dissipation, stiffness, and ductility to identify the optimal geometric configuration. The results indicate that the EA3UED exhibits high energy dissipation, strength, stiffness, and ductility alongside cost-effective benefits. Two primary failure modes were observed: U-shape failure and bolt fractures. The validated finite element models successfully simulated the hysteretic behavior of the EA3UED. And a parametric study based on these models examined the effects of the width of U-shape and the steel grade on the device performance. These improvements demonstrate the EA3UED’s potential for integration in future bridge pier designs, improving their resilience and performance under seismic loads.

Bending performance of RC beams reinforced with UHPFRC strips with different geometry and positions

Bending performance of <scp>RC</scp> beams reinforced with <scp>UHPFRC</scp> strips with different geometry and positions

A Study on the Mechanism by Which Graphene Oxide Affects the Macroscopic Properties and Microstructure of Abrasion-Resistant Ultra-High-Performance Concrete (UHPC)

To further enhance the abrasion resistance of UHPC in demanding abrasion environments, this study investigated the effects of graphene oxide (GO) on the workability, mechanical properties, and abrasion resistance of UHPC. Utilizing 27Al Nuclear Magnetic Resonance (NMR), 29Si NMR, microhardness, and BET analysis, the study analyzed the mechanisms through which GO influences UHPC’s microstructure in terms of abrasion resistance. Additionally, molecular dynamics simulations were employed to examine the mechanisms by which GO enhances UHPC’s abrasion resistance at the nano and micron scale. The findings show that an optimal amount of GO can improve the mechanical properties and abrasion resistance of UHPC. When 0.03% of GO (by cementitious material mass) was incorporated, the impact on workability was minimal, yet compressive strength increased by approximately 1.80%, flexural strength by 3.02%, impact wear resistance by 1.78%, the abrasion loss rate decreased by 10.01%, ultimate impact energy increased by 1.76%, and the toughness index improved by 10.10%. GO enhances abrasion-resistant UHPC primarily by increasing hydration, refining pore structure, and improving the microstructure of the interfacial transition zone. While GO increases the hydration degree of the UHPC matrix, it does not alter the silicate chain in C-A-S-H gels within the paste. Additionally, the incorporation of graphene oxide can refine the pore structure of the UHPC cement paste and improve the microstructure of the interfacial transition zone (ITZ) between the aggregate and the cement paste. The molecular dynamics simulation reveals that, under abrasive forces, GO forms strong, stable chemical bonds with the C-A-S-H base atoms, significantly enhancing the abrasion resistance of C-A-S-H.

Tribologically enhanced self‐healing hybrid laminates for wind turbine applications

AbstractWind turbines are subjected to extreme weather and load conditions; hence, high strength and impact resistance are required. Furthermore, wind turbine blades can be subjected to impact loads such as bird strikes, resulting in the formation of microcracks. Self‐healing capsules can be used to mend turbine blades for microscale damage. The incorporation of self‐healing capsules may cause a decrease in the mechanical characteristics of the composites prior to impact resistance, which can be compensated for with efficient fillers such as silicon carbide whiskers (SiCw). Thus, a novel hybrid composite structure is examined with the advantage of using a self‐healing mechanism and SiCw reinforcement. Tensile, tribological, and Charpy impact tests were performed to characterize the mechanical and tribological properties, which were supported with microscopic observations. Multiple experimental characterizations were performed to investigate the impact, and the ultimate tensile strength (UTS) and energy absorption capacity of the structure were shown to increase by 32% and 45%, respectively, with the addition of SiCw. The presence of self‐healing agents provides a 5% rise in UTS after enough time for healing following the collision. The structure's tribological performance is improved by 10% in wear resistance and 20% in friction coefficient.Highlights Hybrid laminated composite structure with silicon carbide whisker and self‐healing capsules. Tensile and Charpy impact tests conducted with microscopic observations Increased ultimate tensile strength and energy absorption capacity by 32% and 45%. Tribological improvement by 10% in wear resistance and 20% in friction coefficient.

Optimizing Hot Forging of 38MnSiVS5 Steel: A Multi-Objective Approach with Grey-Fuzzy Method

The present research focuses on the hot forging of 38MnSiVS5 micro-alloyed steel, examining the impact of key process variables, such as working temperature, deformation percentage and rate of cooling on mechanical properties, notably the ultimate tensile strength and impact energy. To optimize the process, Taguchi's parametric design, utilizing an orthogonal array in combination with grey relational analysis and fuzzy logic analysis, has been implemented. By applying grey-fuzzy logic analysis, the optimization of complex multiple responses is streamlined into a single grey-fuzzy reasoning grade. The study employs the Grey fuzzy logic method to concurrently optimize both responses. The grey-fuzzy reasoning grade serves as a performance index, aiding in the determination of the optimal process parameter settings for both the ultimate tensile strength and impact energy responses simultaneously.

Mechanical Characterization of Non-degraded Porcine Annulus Fibrosus Material Properties.

Porcine cervical spines are commonly used as a surrogate for human lumbar spines due to their similar anatomic and mechanical characteristics. Despite their use in spinal biomechanics research, porcine annulus fibrosus (AF) yield and ultimate properties have not been fully evaluated. This study sought to provide a novel dataset of elastic, yield, and ultimate properties of the porcine AF loaded in the circumferential direction. AF specimens were dissected from porcine cervical spines (C3/C4-C6/C7) oriented in the circumferential direction. Specimens were uniformly hydrated before being quasi-statically distracted to failure. Linear modulus, yield stress and strain, ultimate stress and strain, and ultimate strain energy density were calculated. Differences between spinal levels, circumferential regions, and radial regions were identified using multifactor ANOVA tests. AF specimens showed a regionally dependent response between outer and inner radial regions, but not between spinal level and circumferential region. The outer region was significantly stronger and stiffer than the inner regions. In both outer and inner tissue, mechanical yield occurred at approximately 80% of their ultimate properties. This study generated a novel dataset of elastic, yield, and ultimate properties of the porcine AF. The data can be used in future research that requires a robust database of healthy, non-degenerated AF mechanical properties, such as the development of future finite-element models.

Behaviour of hollow ultra-high-performance concrete-high strength steel columns for wind turbine towers with different confinement forms subjected to combined loads

This paper investigates the behavior of circular hollow ultra-high-performance concrete (UHPC) columns reinforced with high-strength steel (HSS) tubes or reinforcements under combined loads, addressing a significant research gap in the application of UHPC for wind turbine towers. Previous studies have primarily focused on conventional towers, lacking comprehensive comparisons of the performance of UHPC columns with various HSS confinement forms such as hollow reinforced concrete (HRC), concrete-filled double-skin steel tubular (CFDST), internally confined hollow reinforced concrete (ICHRC), and externally confined hollow reinforced concrete (ECHRC). To bridge this gap, an experimental study was conducted on four different confinement forms of hollow circular UHPC columns: CFDST, ECHRC, ICHRC, and HRC. These columns were subjected to combined loads of constant compression and cyclic bending. The performance of five specimens was assessed by comparing failure modes, hysteresis curves, ultimate capacity, stiffness degradation, ductility, and energy dissipation, identifying cost-effective confinement forms. The study revealed that UHPC-HSS composite columns exhibit characteristic bending damage modes, with external steel tubes significantly enhancing their ultimate capacity and energy absorption. Replacing the internal HSS tube with reinforcements increased the load-bearing capacity by up to 5.6%. Substituting external steel tubes with steel bars leads to an 18%-27% reduction in load-bearing capacity. In terms of ductility, CFDST columns showed notable improvements, with a 2.8% increase over ECHRC column and a 7.53% increase over ICHRC column. The ECHRC column was identified as the most cost-effective, while CFDST columns, although high-performing, incurred higher costs. Finite element simulations of specimens were developed and validated the experimental results, with errors under 10%. Finally, the feasibility of predicting the ultimate strength of the columns using existing methods was evaluated based on the experimental data.

Effects of bedding angles on rockburst proneness of layered anisotropic phyllites

To examine the effect of bedding angle upon burst proneness in terms of energy, phyllites with seven various bedding angles are selected for conventional uniaxial compression and single-cyclic loading–unloading uniaxial compression tests. The ejection and failure during compression process of phyllites are monitored in real-time by high-speed camera system. The results demonstrate that the phyllites with different bedding angles all consistently follow the linear energy storage and dissipation (LESD) law during compression. The ultimate energy storage of phyllites with varying bedding angles can be calculated precisely via using the LESD law. Based on this, four kinds of energy-based rockburst indices are applied to quantitatively assess the burst proneness for phyllites. Combined with the recorded images of high-speed camera system, ejection distance, and mass of rock fragments and powder, the burst proneness for phyllites with various bedding angles is qualitatively evaluated adopting the far-field ejection mass ratio. Next, burst proneness of anisotropic phyllites is assessed quantitatively and qualitatively. It is found that phyllites with bedding angles of 0°, 15°, and 90° have a high burst proneness, and that with bedding angle of 30° has a medium burst proneness, whereas the ones with bedding angles of 45°, 60°, and 75° have a low burst proneness. Finally, the published experimental data of shale and sandstone specimens with different bedding angles are extracted, and it is preliminarily verified that the bedding angle does not change the LESD law of rocks.

Nonlinear Finite Element analysis of concrete corbels with hybrid reinforcements

This study utilizes nonlinear finite element analysis to simulate the structural response of Reinforced Concrete (RC) corbels with hybrid reinforcements under monotonic loading. The models implemented in ABAQUS examine RC corbels with combined Carbon Fiber Reinforced Polymer (CFRP) and steel reinforcing bars to study the interaction between the concrete and hybrid reinforcement system. Specifically Ultimate load capacity, energy absorption and failure mode. Compressive strength, shear span/depth ratio, and the ratio of CFRP/steel reinforcement were the main parameters that considered in this paper. Results demonstrated a significant improvement in the ultimate load capacity of concrete corbels by up to 53% when both conventional steel and CFRP bars were integrated within the concrete corbel. The numerical test outcomes revealed that an increased hybrid reinforcement ratio effectively managed crack distribution, resulting in reduced concrete crack widths.

Punching shear performance of reinforced concrete slab-to-steel column connections incorporating ECC and UHPECC

Unlike the conventional reinforced concrete (RC) slab-column connection, the punching shear generated at the RC slab-to-steel column connection may lead to brittle punching shear failure due to the small area around the steel column. Moreover, the unexpected moments arising from eccentric loading can also lead to the failure of the slab in punching shear mode. This paper proposes employing high-performance concrete (HPC) to fill the critical punching shear zone to improve the punching shear resistance of RC slabs to steel column joints. Experiments on eight RC slabs to steel column connections are reported. The test parameters under investigation are the type of HPC used to fill the critical punching shear zone, the distance (S) of the HPC zone measured from the flanges of the steel column and loading condition (concentric and eccentric). The types of HPC include engineered cementitious composite (ECC) and ultra-high performance ECC (UHPECC). The experimental results show that the proposed techniques can significantly improve the cracking load, elastic stiffness, energy absorption capacity, ductility, failure modes, and ultimate load of the slab-to-column connections. The ultimate load of the tested connections is increased by as much as 33 %, and 28 % for the slabs subjected to concentric and eccentric loading, respectively. However, the ultimate load and energy absorption capacity of the slab with UHPECC having a S value of 1d, where d is the effective depth are lower than those of the control slab. Three-dimensional nonlinear finite element models are developed to simulate the performance of tested slab-to-column connections and validated by experimental results. The parametric study shows that the n (=S/d) value greater than 3.5 has insignificant effects on the ultimate punching shear capacity of the slab. It is demonstrated that the proposed formulas faithfully estimate the ultimate punching shear capacity of slab-to-column connections constructed with different HPCs under concentric and eccentric loadings.

Influence of opening shape, size and position on the ultimate strength, stiffness and energy dissipation of confined brick masonry walls

Influence of opening shape, size and position on the ultimate strength, stiffness and energy dissipation of confined brick masonry walls

Non-monotonic effect of differential stress and temperature on mechanical property and rockburst proneness of granite under high-temperature true triaxial compression

Complicated geological conditions such as high geo-stress and high ground temperatures often have a significant impact on the mechanical behavior and failure potential of hard rocks in deep engineering. This study aims to investigate the mechanical behaviors and rockburst proneness of granite under high differential stress and high temperatures in deep-buried high-temperature tunnels. A comprehensive experimental study was conducted on the coupling behavior of granite under high-temperature and high differential stress by true triaxial compression tests. The strength and failure mechanism of granite as well as their relationship with high temperature and high differential stress were revealed. The rockburst proneness of granite from a deep-buried high geothermal tunnel was assessed based on the rock's ultimate energy storage characteristics. It shows the strength, failure mechanisms, and rockburst proneness of granite, are significantly correlated to the granite high-temperature high-stress conditions. The temperatures extend the strengthening range of the intermediate principal stress on the true triaxial peak strength of the granite. With increasing temperature and differential stress, secondary vertical cracks develop quickly to induce the macroscopic failure of granite. Under high temperatures, the failure of granite changes from compressive-shear failure to tensile-shear failure at low differential stress. High temperature coupled with high differential stress strengthens approximately 1.14 times the rockburst proneness of granite. The results are important for the safe construction, and disaster assessment of deep-buried high geothermal tunnels.

Influence of polypropylene fibers on the tensile mechanical properties of calcium silicate hydrate: molecular simulation.

This research assesses the influence of polypropylene (PP) fibers, both homopolymer and hydroxylated (PPOH), on the tensile properties of calcium silicate hydrate (C-S-H) composites through molecular dynamics (MD) simulations. Our models explore C-S-H matrices integrated with PP and PPOH fibers at varying polymerization degrees. The results demonstrate that both PP and PPOH fibers significantly influence the tensile strength and Young's modulus of the composites. Notably, PPOH fibers contribute to more substantial mechanical enhancements than PP, attributed to the increased polarity and enhanced intermolecular interactions from the hydroxyl groups. The study reveals a nonlinear relationship between polymer additive content and mechanical performance, with optimal properties at a polymerization degree of 20. Additionally, stress-strain analysis indicates that PPOH composites exhibit superior ductility and fracture energy, particularly at polymerization degrees of 20, showing enhanced ultimate strain and fracture energy by up to 9.6% and 13.9%, respectively, compared to PP counterparts. These results highlight the crucial role of tailored polymer additive composition and chemical modifications in maximizing the mechanical efficacy of C-S-H-based materials, enhancing their durability and structural performance. All MD simulations were conducted using LAMMPS. The models employed a combination of Clayff and Cvff force fields. During the entire tensile simulation, the system was configured under the NPT ensemble at 300K.

Seismic behavior of prefabricated lightweight steel composite frame-sandwich wall with enhanced border structure

An innovative prefabricated lightweight steel composite frame-sandwich wall with an enhanced border structure (LSCF-SW), suitable for low-energy consumption low-rise residences, is proposed. Low cyclic loading experiment were conducted to study its seismic behavior. The main parameters include wallboard border type (composite border, mixed border) and steel reinforcement strength (HRB450, HRB500). One full-scale LSCF specimen and four full-scale LSCF-SW specimens are prepared, and their seismic behavior is investigated in terms of failure mode, hysteretic characteristics, ultimate bearing capacity, stiffness degradation, deformation capacity, energy dissipation, and strain characteristics. The results revealed that the sandwich wall (SW) with an enhanced border and lightweight steel composite frame (LSCF) is the primary and secondary seismic fortification lines of the structure, respectively. The LSCF-SW structure exhibited a damage evolution process with four stages. The failure mode involving concrete crushing at the bolted connection area is observed in the specimens with composite bordered sandwich walls (LSCF-SWC), and dense diagonal cracks are discovered in the specimens with mixed bordered sandwich walls (LSCF-SWM). Compared to LSCF-SWC specimens, the ultimate load of LSCF-SWM specimens increases by 23.0 %–50.3 %, and the initial stiffness improves by 16.3 %–42.3 %. The deformation capacity of LSCF-SWC specimens is superior to that of LSCF-SWM specimens. As the steel reinforcement strength increases, the ultimate bearing capacity and initial stiffness of the LSCF-SW also rise. A shear model for the bolt group and a local bending model for the wallboard border are proposed, establishing an ultimate bearing capacity calculation method for LSCF-SW. The calculation results closely align with the experimental results.

Seismic behavior of exterior joint of CFDST column to steel beam with RC slab

To investigate the seismic performance of an exterior joint connecting concrete-filled double-skin steel tubular (CFDST) column to steel beam with reinforced concrete (RC) slab, four scaled-down joint specimens were designed at a ratio of 1:2. Quasi-static tests were conducted with different axial compression ratios were performed, and the failure mode, hysteresis curve, skeleton curve, bearing capacity, energy dissipation capacity, strength and stiffness degradation, and strain analysis of the composite joint were analyzed. A finite element method (FEM) model of the joint was constructed and validated against the obtained experimental results. Additionally, a parametric study was carried out to investigate the influence of various factors, including the hollow ratio of the CFDST column, the concrete strength of the slab, the thickness of the slab, and the width-to-thickness ratio of the outer steel tube on joint. Based on experimental studies and finite element analysis (FEA), a theoretical calculation method was proposed to evaluate the flexural capacity of the composite joints. The test results showed that the composite exterior joint specimens with RC slab failed at the beam end. Typical failure phenomena of fracture at the steel beam and horizontal end plate interfaces, steel beam flange buckling, and concrete crushing at the RC slab were observed in the experiments. While the interior joint specimen experienced significant plastic deformation and buckling at the column flange. The hysteresis curve of the specimen is elliptical and full without pinching. The presence of RC slab can effectively improve the ultimate bearing capacity, initial stiffness and energy dissipation capacity of the specimen. The FEA results show that the bearing capacity of the composite joints was improved significantly with the increase of the thickness of the slab and the width-thickness ratio of the outer steel tube. The theoretical calculation results of the flexural capacity of the joint are 86 %–112 % of the results of the finite element calculation. The stability and accuracy of the calculation method are excellent and can be effectively applied to calculate the flexural capacity in CFDST composite structural systems.

Experimental and numerical study on flexural performance of ultra-high performance concrete frame beams reinforced with steel-FRP composite bars

This paper presents the bending tests of four ultra-high performance concrete (UHPC) frame beams and one normal strength concrete (NSC) frame beam, all reinforced with steel-FRP composite bars (SFCBs). A comprehensive analysis was carried out, encompassing evaluation of the failure mode, crack propagation, bearing capacity, deformation, strain response, and plastic rotational capacity of the frame beams. Investigating the effects of concrete type, reinforcement type, and beam-end reinforcement ratio on the flexural performance of the frame beams was a key aspect of this study. A three-dimensional finite element (FE) model of the frame beam was established and rigorously verified. The developed model enabled a detailed parametric analysis involving the steel ratio, the yield strength of the inner core steel bar, the elastic modulus of the FRP, and the ultimate tensile strength of the SFCB. The results indicated a consistent failure mode of all frame beams: crushing of concrete at the beam-end, initiating a sequence of plastic hinge occurrence starting at the beam-end and then progressing to mid-span. The substitution of normal strength concrete with UHPC significantly enhanced various aspects of the frame beams, including the flexural capacity, deformation, ductility, ultimate energy dissipation, and plastic rotational capacity, while inhibiting the generation and expansion of cracks. Notably, the plastic rotation angle of SFCB-UHPC frame beams was 4.9 times greater than those of steel-UHPC frame beams, emphasizing the effectiveness of SFCB in enhancing the beam-end plastic rotational capacity. A decrease in the beam-end reinforcement ratio significantly reduced the flexural capacity, ultimate energy dissipation, and beam-end plastic rotational capacity, while improving ductility. Additionally, the study established a formula for calculating the equivalent plastic hinge length, utilizing the relative compressive zone height and effective section height of the beam-end controlling section as variables, which demonstrated good alignment between predicted and experimental results.

Damage and energy characteristics of coal rock combinations with inclined coal seams under axial loading

A single load compression test of rock-coal-rock assemblages (RCRs) containing coal bodies with different inclinations was carried out with the research background of mining deep, large-steep coal seams. It was found that the larger the inclination angle of the coal body in the RCR samples, the larger the compaction stage of the samples and the smaller the uniaxial compressive strength value. In addition, both the maximum acoustic emission (AE) energy of the samples and the cumulative AE energy at the moment of destruction decreased with the increase of the inclination angle of the coal body in the form of exponential relativities. Also, the input energy and ultimate elastic energy of the samples at the peak stress moment decreased with increased inclination angle of the coal body. Furthermore, both of them changed with the inclination angle of the coal body in accordance with the exponential relationship; meanwhile, when the applied load exceeded the peak strength, the dissipative energy of the RCR samples increased rapidly due to the loss of load-bearing capacity. At the peak moment, the percentage of dissipated energy of the samples increased exponentially with the increase of the inclination angle of the coal body. This study has certain reference significance for the prevention and control of dynamic disasters during the mining of large angle coal seams.

Characterization and optimization of TIG welding parameters for AISI 304 and AISI 316 stainless steel dissimilar joints

This study explores the impact of tungsten inert gas (TIG) welding parameters on the mechanical properties and microstructure of dissimilar welds between AISI 304 and AISI 316 austenitic stainless steels. Given the growing industrial demand for these materials, the research focuses on optimizing welding current, shielding gas flow rate, and voltage to enhance tensile strength, hardness, and impact toughness. Using the L9 orthogonal array based on Taguchi’s methodology, the experiments revealed that Relatively highs currents and voltages significantly improved the ultimate tensile strength (up to 673.67 MPa) and impact energy absorption (up to 36.5 J). Microstructural analysis indicated refined grain structures in the heat-affected zones, with pronounced grain growth in AISI 316 due to its thermal sensitivity. The micro-hardness analysis revealed that the highest hardness occurred in the HAZ of AISI 304, with samples 5 and 6 exhibiting the optimal hardness profile, reflecting the most favorable welding parameters. The study concludes that a current range of 80-90 A and a voltage range of 10-11 V and a shielding gas flow rate of 12-16 L/min provide optimal welding conditions, offering robust guidelines for industrial applications requiring high-performance dissimilar welds.

Emerging Two-Dimensional Materials for Proton-Based Energy Storage.

The rapid diffusion kinetics and smallest ion radius make protons the ideal cations toward the ultimate energy storage technology combining the ultrafast charging capabilities of supercapacitors and the high energy densities of batteries. Despite the concept existing for centuries, the lack of satisfactory electrode materials hinders its practical development. Recently, the rapid advancement of the emerging two-dimensional (2D) materials, characterized by their ultrathin morphology, interlayer van der Waals gaps, and distinctive electrochemical properties, injects promises into future proton-based energy storage systems. In this perspective, we comprehensively summarize the current advances in proton-based energy storage based on 2D materials. We begin by providing an overview of proton-based energy storage systems, including proton batteries, pseudocapacitors and electrical double layer capacitors. We then elucidate the fundamental knowledge about proton transport characteristics, including in electrolytes, at electrolyte/electrode interfaces, and within electrode materials, particularly in 2D material systems. We comprehensively summarize specific cases of 2D materials as proton electrodes, detailing their design concepts, proton transport mechanism and electrochemical performance. Finally, we provide insights into the prospects of proton-based energy storage systems, emphasizing the importance of rational design of 2D electrode materials and matching electrolyte systems.

Micro-structure evolution, precipitation behavior and strengthening mechanism of Ni-Cr-Mo system steel fabricated via laser powder bed fusion and subsequent quenching control

High-performance 24CrNiMo steel was fabricated using Laser Powder Bed Fusion (LPBF). Subsequent quenching treatment was applied and the influence of quenching temperatures on micro-structure evolution and properties was systematically characterised and analysed. The micro-structure of the as-built steel consisted of two parts. The first part comprised martensite with twins combined with ω-Fe nano-particles, and the second part consisted of lower bainite in the molten pool, as well as upper bainite, granular bainite and tempered martensite in the heat-affected zone. With the quenching temperatures varying from 800 °C to 950 °C, the micro-structure gradually transformed from acicular ferrite + martensite to tempered martensite +θ-Fe3C carbides, and the grain size exhibited noticeable growth. Moreover, quenching treatments could eliminate the anisotropy and inhomogeneity of the micro-structure. The rod-shaped nanosized η-Fe2C and θ-Fe3C precipitates were clearly observed, which were converted from ω-Fe and distributed at multiple angles in the lath. The size and number of nano-precipitates, triggered by the high self-tempering degree of martensite, gradually increased. The relationships among grain size, the twins, dislocation density and nano-precipitation and the dramatically improved performance of quenched samples were analysed using strengthening mechanisms. After quenching at 850 °C, the as-built 24CrNiMo steel attained ultra-high mechanical properties including hardness, Ultimate Tensile Strength (UTS), Elongation (El) and impact energy with values of 480.9 HV1, 1611.4 MPa, 9.8% and 42.8 J, respectively. Meanwhile, both the wear and thermal fatigue resistance increased by approximately 40%. This study demonstrated that LPBF-fabricated 24CrNiMo steel, with matching good performances, can be achieved using a subsequent one-step quenching process.